Ladder



April 7, 1931. H. A. THOMPSON LADDER Filed Feb. 26, 1929 INVENTOR WITNESS 5591 9 fiam 6am, BY @fi ATTORNEY Patented Apr. 7; 1931 HENRY .ALISIER THOMPSON, OF YAKIMA, WASHINGTON LADDER Apphcation filed. February 26, 1529. Serial No. 342,768.

7 This invention relates to ladders of the type known as step ladders.

A primary object of the invention is to so construct la der of this character as to eliminate the use of metal rods employed as supports for the steps and at the same time provide a maximum strength with less weight and greater rigidity throughout.

line 44 of Fig. 2;

ladderconstructed in accordance with this invention; 1

Fig. 2 is an enlarged detail side elevation;

Fig. 3 is a transverse section taken on the line 3-3 of Fig. 2;

Fig. 4 is a horizontaldsection taken on the an Fig. 5 is a detail perspective view of the rung bracing plate and stirrup.

In the embodiment illustrated a ladder 1 is shown which may be of any desired length and size andwhich comprises the usual side bars 2 and 3 with transversely arranged longitudinally spaced steps or rungs 4 connecting them and which are designed to support the weight of the user. The side bars are preferably constructed of wood as are also the steps 4C. These steps 4 have secured to their lower faces at a point midway the width thereof longitudinally extending ribs 5, it being understood that each step has a single rib. The grain of the wood of the step and its rib is different, said rib being riveted to the step as shown at 6. This construction while relatively light in comparison with the iron or steel rods used adds approximately to the strength of the step.

At each end of each step 4 is a U-bolt 7 which extends through the rib 5 and the adjacent side bar, one of the rivets 6 passing through the bolt at its closed end as shown clearly in Fig. 4. The free ends of the bolt 5 which project beyond the side bar of the ladder are provided with nuts 8 which when screwed up tighten the parts and hold them rigidly and securely together. A plate or washer 9 is arranged on the outer face of the side bar of the ladder and through which the legs of the bolt extend as shown clearly in Fig. 4.

Arranged between each end of the rungs or steps at and the adjacent inner face of the side bar oi the ladder is a bracing plate or stirrup 10 having an inwardly extending lateral flange 11 at the upper portion thereof which is shaped to fit over the step 4 at its end while the U-bolt passes through apertures 12 therein and cooperates with theplate to securely hold the step in engagement with the ladder side bar. The plate 10 is also provided with a plurality of out struck prongs 13, two being here shown, which are designed to be imbedded in the side bar as shown in Fig. 4. to assist in holding the parts assembled. As shown in Fig. 2 an inclined washer 9a is disposed between the nuts 8 and the washer 9 to provide for the tightening up of the .U-bolt against the inclined face of the side bar it being of course understood that when theside bars are parallel as shown in Fi g. 1 these washers 9a will not be necessary.

A reinforcing or wear plate flat is shown in Fig. 2 arranged below the rib 5 and through which the rivets 6 are designed to pass.

It will be obvious that use of the U-bolts Jill} both ends of each step or rungs insures a strong gr p and support and provides means which are easily tightened to hold the parts rigidly together. The gist of the invention resides in the self-bracing feature insured-by about two lnches of the step end which renders the ladder sides rigid and .strong.

In Fig. 1 a ladder is shown in which the side bars are made parallel with each other while in Fig.2 the side bar there shown is inclined, ladders being frequently constructed withtheir sidewbars converging towards the upper end.

Without ifurther description it is thought grain of the wood of the step and'the rib extending in different directions, U-bolts extending throughsaid ribs and side bars for connecting the steps to the side bars, and

means for securing said bolts in position.

2. A ladder comprising side bars with steps arranged between them, each of said steps having a rib extending longitudinally of its lower face and riveted to the step, the grain of the wood of the step and the rib extending in different directions, 'U-bolts extending through said rib and side bars for connectmg the step to the side bars and bracingplates arranged between the ends of the step and the side bars, said plates having means for connecting them with the steps and with the side bars and-means for'securlng said .U-bolts in position.

3. A ladder comprising side bars with steps arranged between them, each of said steps having a rib extending longitudinally of its lower face and riveted to the step, the grain of the wood of the step and the rib extend ing in different directions, U-bolts extending through said ribs and sides for connecting the steps to the side bars and nuts for securing said bolts 111 position, bracing plates mounted between thevends of the steps and said ribs being riveted to the step, U-bolts" the adjacent side bars of the ladder, each plate having an inturned flange to fit around the end of the step and outturned' spurs to engage the side bar, the U-bolts passing through said-plate to assist in holding the parts assembled.

4:. A ladder including side bars with steps arranged between I them, a rib extending longitudinally of the lower face of each step,

extending transversely through the ends of the ribs and behind the end rivets, with the legs of the bolts extending parallel with and engaging opposite side faces of the rib, said bolt legs passing through the adjacent side bar of the ladder and nuts for securing said bolts in position and for tightening them up to hold the parts rigidly assembled.

5. A ladder including side bars with steps arranged between them, a rib extending longitudinally of the lower face of each step,

parallel with and engaging opposite side faces of the rib, said bolt legs passing through the adjacent side bar of the ladder, and nuts for securing said bolts in position and for tightening them up to hold the parts rigidly assembled, each step having a plate arranged over the ends thereof and locatedbetween said end and the adjacent face of the ladder side bar, said plate having step encircling means and means for engagement with the ladder side bar, said plate having apertures through which the U-bolts extend.

6. A ladder comprising side bars with steps arranged between them, each of said steps having a rib extending longitudinally of its lower face and riveted to the step, U-bolts extending through said ribs and sides for connecting the steps to the side bars and nuts for securing said U-bolts in position, and bracing plates mounted between the ends of the steps and the adjacent side bars of the ladder, each plate having an inwardly extending flange encircling the top and side portions of the step and having a pair of shoulders upon the lower side defining a seat for the end portion of each step, said shoulders stopping short of the medial portion of said plates and said plates having an aperture formed adjacent each shoulder for the passage therethrough of the legs of the U-bolts. Signed at Yakima, in the county of Yakima and State of Washington, this 21st day of February, A. D. 1929.

HENRY ALISTER THOMPSON.

" said rib being riveted to the step, U-bolts extending transversely through theends of the ribs with the legs of the bolt extending 

